Aegolius acadicus
(Northern Saw-whet Owl)

Order: Strigiformes
Order Description: Owls
Family: Strigidae
Family Description: Typical Owls

Physical Description:
7-8 1/2" (18-21 cm). Small, tame owl. Lacks ear tufts on its flat- topped head and has a short tail. Brown above, lightly streaked with white on the forehead and crownClick word for definition, large white spots on wings; white below with blotchy reddish-brown streakings. Face whitish with yellow eyes and dark bill. Immatures are chocolate brown with broad white eyebrows that form a "V" over the bill.

Similar Species- Boreal Owl, Screech-owls, Pygmy-owls, Flammulated Owl

Song:
A mellow series of low, whistled notes on one pitch; often unevenly spaced and repeated mechanically up to 130 times per minute: took took took took took took etc.

Distribution:
Breeds from southern Alaska, east across portions of Canada to New Brunswick, and south to southern California, southern Arizona, southern Mexico, western Texas, Missouri, southern Minnesota, and Maryland. Also breeds in Great Smoky Mountains. Winters generally throughout breeding range (some southward withdrawal), and irregularly or casually south to southern United States.

Habitat:
Found in dense coniferous or mixed forests, cedar groves, alder thickets, swamps, and tamarack bogs. When not breeding, found in dense second growth, brushy areas, arid scrub, and open buildings. In Idaho, less abundant in higher-elevation spruce/fir forests, but is the most abundant owl in mid-elevation conifer forests.

Diet:
Eats mainly small mammals (e.g., deer mice, voles, and shrews), and sometimes birds and insects. In Idaho, eats higher proportion of very small mammals (2-15 g).

Ecology:
Nests in natural or abandoned cavity in tree. Throughout range, often roostsClick word for definition in dense evergreens in winter. Hunts at night. Apparently obtains prey mainly by pouncing from above, after short flight from elevated perch. In Idaho, defends exclusive territories. Limited data on breeding density suggest maximum of few pairs/km2.

Reproduction:
Female incubatesClick word for definition about 5-6 eggs for 26-28 days. Young first fly at 4-5 wk. Nest-box study in southwestern Idaho revealed polygynyClick word for definition (1 male mating with > 1 female) in Saw-whets.

Conservation:
Element Code: ABNSB15020
Status: Protected nongame species
Global Rank: G5
State Rank: S4
National Rank: N5B,N5N

Important State References:
Marks, J.S., J.H. Doremus, and R.J. Cannings. 1989. Polygyny in the Northern Saw- whet Owl. Auk 106:732-734.

Photos by Peter S. Weber,© 2000, and Jeff Spendelow,© 1999
Design by Ean Harker©1999, 2000.
Written by Jason Karl, 2000.